[HAM] Unwanted distortion on an L100

[Dave Bishop]

Tubes, caps and connectors.  You might operate all of the switches and see 
whether the distortion is different in any particular configuration.  I 
would open all the Molex connectors you can locate and spray them and the 
tube sockets with De-Oxit.  Then I would lightly tap or wiggle each tube 
with a pencil eraser and listen for a microphonic tube.  Try swapping out V 
9 and V 10, the 6BQ5 tubes.  You can also trade the 12AX7s and see if the 
distorition changes.  Check out the two cap cans in the center of the power 
amp, C316-C319.   Turn over the amp chassis, and look for darkened or burned 
resistors, particlarly the ones going to pin 2 of the V 9 and V10, or check 
their resistance if you have a meter to see if they are going high.  If that 
turns up nothing, post back and the list can suggest more ideas.

Regards,

Dave Bishop